Pilot burner



Dec. 1, 19 64 ZULIAN PILOT BURNER Filed Aug. 11. 1961 INV ENTOR.

ALDO ZULIAN BY hmd 5m 51% Ma ATTORNEYS United States Patent 3,15%293PHOT BURNER Aldo Zulian, Yukon, Pa, assignor to Robcrtshaw ControlsCompany, Richmond, Va, a corporation of Delaware Filed Aug. 11, 1961,Ser. No. 130,979

11 (llaiins. (Cl; 158123) low rate non-aerated pilot flame for ignitinga main burner and a low rate aerated pilot flame ignited thereby inresponse to the initiation of intermittently supplied gas'or other fluidfuel under control of some demand signal of external origin. It pertainsto safety control of the primary fuel supply inasmuch as the main.burner fuel supply is turned on preferably only in response to theheating of a temperature sensitive control following the ignition of theaerated fuel supply positioned adjacent to the constant pilot flame.

Various arrangements are known for employing a heater burner suppliedintermittently with fuel to heat a control element by means of which amain burner fuel supply controlled. In such arrangements itisconventional for a constant burning pilot flame to be employed forignition of the intermittent burner which serves to actuate a controlinitiating'the supply of tfuel'to a main burner and thereafter to ignitethe fuel at the main burner-.-

The primary object of the invention is to provide a safer unit which isalso easy and inexpensive to manufacture while employing very low ratesof consumption of fuel both in .the constant burner and the intermittentburner units. i

I A further object of the invention is to provide for readyadjustability of the flame from both intermittent and steady burnerunits in accordance with the type of gas or fluid fuel employed, over awide range of pressures.

A still further object of the invention is to provide a unitary flamecontrol structure which is easily disassembled for cleaning of thosepar-ts which may come in contact with the intermittent orthe constantburner flames.

Other objects will be apparent as the description pro coeds, and byreference to the drawings in which:

FIG. 1 is an elevational view of a burner control unit incorporatingthis invention;

FIG 2 is a sectional view of the burner unit taken along line 2-2 ofFIG. 1;

FIG. 3 is a plan sectional view taken through the device of FIG. 2 alonglines 3-3; and

FIG. 4 is a perspective view of a portion of the device of thisinvention showing a constant burnerflame retainer and heater burnerflame spreader as an integral unit.

easily adjusted and variably useful for the control of the intermittentand constant burning pilot burner portions of the device. A structure isprovided to assure stable operation both of the intermittent pilot andthe constant burning pilot at very low rates of fuel consumption. Thiscontributes to safety of the device for the reason that very little fuelis permitted to escape even though unignited fuel might be issuing fromboth the intermittent and standby fuel nozzles if the constant flameshould be This invention provides a compact structure which isextinguished. The pilot burner unit hereof [further has means forconserving fuel for the intermittent or heater unit and has a highlyeffective constant flame retainer unit which is particularly stableagainst atmospheric shock or variations in fuel supply and is adjustablefor fuel of many kinds. The improved structure so provided permitssimplicity and economy of manufacture, ease of cleaning and readyadjustment to accommodate various pressures and types of fuel which maybe employed.

In the preferred embodiment illustrated in the drawings a common supportand body member 1 is shown equipped with fittings 2 and 3 connected whenin operation, respectively, to a steady fuel supply and to anintermittent fuel supply, the latter under control of a demand signal bywhich it is desired to initiate operation of a main burner (not shown)or other thermally actuated device. The constant fuel supply at 2 wouldnormally be supplied through a shutofl valve for elimination of theconstant flame in periods of non-use. The fuel supplied to fitting 3 isintermittent in character and is controlled in accordance with thepurposes to which the.

safety pilot unit may be put. For example, when the unit is intended toignite the main burner (for a gas hot water heater, or like device, thefuel may reach fitting 3 by Way of a valve from a main supply, whichvalve may be under thermostatic control, either to open or close thesame in accordance with demand indicated by a temperature sensitiveelement associated with the device to be heated. When the uni-t isapplied to the ignition of a heater in an-oven, broiler, clothes dryeror the like, con trol of the fuel to fitting 3 may be by way of aswitch-operated solenoid valve, or the like. Details of theseconnections do not form a part of this invention and are,

therefore, not described in further detail.

Fittings 2 and 3 are preferably removable for cleaning, being generallyscrew-connected into base 1,.as indicated by nuts 4 and 5. In order toeffect a low rate of fuel consumption and to provide clean burningflames, fittings 2 and 3 are provided at the inner ends thereof, respectively, with fluid limiting orifices or jets 6 and 7 of small diameterrelative to the dimensions of the burner orifices about to be described.Aligned with fuel jet 7 there is a duct or conduit 8 which terminates innozzle opening 9 disposed to face a control element 3b which, whenheated may be arranged to actuate a main burner fuel supply or othercontrolled unit. Conduit 8 is mounted on base 1 in axial alignment withfitting 3 adjacent to jet 7. Concentrically disposed about thelongitudinal axis of conduit 8 is a second conduit ltl preferablysurrounding conduit 8 as shown in FIGS. 1 and 2. Conduit 10 terminatesin a burner orifice 11 generally of circular form and of substantiallygreater diameter than jet 6 in order to provide a lowered exit velocityfor the fuel delivered thereto. Channel 12 suitably formed, as byboring, in base 1 connectsconduit 10 to receptacle 13 into which fitting2 is secured.

The fuel for orifice 11 is preferably not aerated, and receptacle 13 isaccordingly not opened to the ambient atmosphere. Fitting 3 conducts gasthrough jet '7 into receptacle 14 which is preferably freely open totheambient atmosphere whereby air is entrained in conduit 8 by conventionalinjector action. The duct or conduct 8 is conveniently of tubular formand of uniform diameter throughout to avoid any back pressure whichwould tend to spoil the injector action at jet 7 in receptacle l4.Nozzle 9 and orifice 11 are the respective outlets of the concentricconduits and require separation sufliciently to keep the flamestherefrom separate. It is also convenient toconstruct conduit 8 oftubing disposed within a tubular conduit It), conduit 8 being'broughtout the side of conduit It) with a smooth bend l5 permitting unimpededflow r 3 of fuel therein. It may be a simple bent tube supported by base1 in a press fitting or may be screw threaded thereinto as desired. Thesimple construction illustrated provides good entrainment of air atchamber 14 and 'elfects burning gaseous fuel with a small blue flameadjacent nozzle 9.

Orifiice 11 may be formed by turning in the ends of conduit 16 as whenthe latter is formed of tubing, and may be concentrically disposed withrespect to conduit at the outer end thereof. In order to. provide aclean burning blue flame from orifice 11 there is shown a circulararcuately formed flame holding member 16, conveniently pressed from thinmetal sheet or plate which may be cup-shaped or hemispherical with aconvex face disposed across orifice 11 adjusted in proximity thereto andsupported thereover by any .convenient means such as metallic loop 17,which is variably secured in adjustable relation to the outer conduit asillustrated. In order to provide more complete control of the flarnefrom orifice 11 there isprovided a circular protrusion 18 in the convexface of the cupped plate element 16. This protrusion may be embossed orotherwise formed and is of circular form somewhat less in diameter thanorifice 11.

. It is preferably disposed within or adjacent to orifice 11 fice 11forms a convenient means of spreading gas exiting from 11 whereby whenit is lighted a circular blue flame arises around element 16; Thiscupped flame spreading or flame holding unit is thereby heated andserves dual purposes, first of retaining the flame against accidentalmomentary cessation of fuel flow from 11, and also of preventing shockwaves in the vicinity thereof from forcing gas back into conduit 10thereby to extinguish the constant pilot flame. This construction hasbeen found to provide a very stable flame surrounding cupped element 16which is not easily extinguished by pressure waves or by blowing fromany side, inasmuch as the opposite side remains protected to causerelighting of any extinguished portion of the ring of flame.Furthermore, element 16 is easily cleaned of any lint or carbon whichmay form thereon and is of a construction which does not tend to clogfrom these or other causes.

A unit comprising flame keeper 16, frame 25, clamps 26 and flamespreader 19 is a separable unit slid ably mountable on a tubular bodyhaving a pilot burner opening at the end. When adjusted to have theopening 11 partially filled by the protuberancy 10, mechanical shocksare restrained laterally by the portion 18 being within the opening 11.Air "shocks in the region surrounding the burner frequently are observedto extinguish pilot flames and are caused at times by the slamming ofdoors in the vicinity or resonant eifects in the chimney, and the like.Such air shocks, along with more steady wind effects, are prevented fromextinguishing the flame held by the structure described since theorifice 11 can neither be completely closed nor the flame swept from thehemispherical surface around which it is rising.

Nozzle 9 is preferably disposed at an angle to the main portion ofconduit 8, shown concentrically within conduit 19 but extendinglaterally therefrom. In order to minimize the quantity of fuel requiredat nozzle 9, paired flanges 19 are preferably disposed laterally ofconduit 10 and laterally enclosing nozzle 9 whereby the flame issuingtherefrom may be longitudinally spread and directed as desired along anysuitable elongated thermo-responsive device shown generally at 30-.

The control element 30 may usually be employed for the purpose ofoperating a main gas supply valve in response to an electrical signalgenerated therein upon the heating of the element 30 by the flame fromnozzle 9. Accordingly, the device 30 is preferably disposed parallel toconduits 8 and 10 and the flanges 19 are positioned in close proximityto the latter as hood means or flame spreading means directing all flameusefully upon element 30 in order that a small quantity of aerated pilotgas will be suflicient for prompt heating and operation of the device30. The device 30 is preferably mounted on base 1 by means of a clampingdevice shown generally at 20 and is secured therein by a screw fittingi-nadjustable position with respect to the nozzle 9 and flanges 19. Thedevice 30 may conveniently be clamped between elements 22 and 23 byscrew 21, one of which is attached to bracket 20, which in turn ispreferably arranged for slidable mounting on a protrusion 24 extendingfrom base 1. Control of the distance from nozzle 9 to device 30 is thusachieved.

In order to provide fine adjustment of the direction of passage 27formed byjaws 28 and 29 at the extremities of flanges 19, there areattached thereto spring members 26 suitably arranged to engage inslidable contact the exterior of conduit 19. For ease in manufacture,flanges 19 and elements 26 may be formed of a single piece by stampingor other suitable operation and loop 17 bearing element 16 is attachedto thebase of flanges 19, as at 25 to form a separable flame controlunit. In a preferred .construction, the spring clip elements 26 areintegrally formed from the same piece as flanges 19, loop 17 and element16, and the flanges 19 terminate in jaws 28 and 29. The pair of springclips 26 thus form the sliding contact with conduit 10 and may beadjusted therealong as desired to secure variations in the opening atorifice 11. When conduit 10 is of circular tubular form, as shown,flanges 19 may be rotated about conduit 19 in lateral adjustment todirect flame from nozzle 9 precisely upon control element 30. To avoidleakage of fuel from the outer conduit around nozzle 9 of the innerduct, duct 8 may be pressfitted or Welded into an aperture in the outerconduit wall as at 31.

The combined structure comprising conduits 8 and 10 may be removed forservicing from their concentric seats in base 1 when held therein merelyby close friction fitting.

So constructed and assembled, the safety burner pilot assembly may bevaried to suit differing fuels and differing rates of burning beingadjustable with respect to flow of gas from both the constant orifice 11and the intermittent heater nozzle 9, by varying the position of clips26 on conduit 10, by varying the support loop 17, and by changing thegap between jaws 28 and 29. The flame holding and directing features arecombined in a single removable unit of simple manufacture and eflicientfuel conserving design, which provides one of the safety features of theunit since so little gas need be employed for eitheror both pilots, thatfire danger is minimized should the gas to the pilot flame around holder16 be accidentally turned off and later turned on again withoutrelighting at orifice 11.

Under these conditions, the main burner would not be lighted because offailure to operate device 31), but the minute stream of gas to the pilotwould remain unconsumed and pass harmlessly through the chimney.

While many uses are contemplated, the safety burner will often beoperated with gas continuously emitted from orifice 11 and burned aroundflame holder 16. Upon demand of an external control device gas isadmitted at 3,

passing through jet 7 to entrain air at 14 which mixes with the fuel inconduit 8 which is of small diameter and thermal conductivity such thatflame does not propagate therein, and exists at 9 where it is ignited bythe flame surrounding 16. The flame at 9 is directed in a variablechannel against control unit 39. Upon the heating of 30 a main supply ofgas is turned on by control mechanism not a part of this invention andnot herein illustrated since it may be of many kinds. When a burner isto be ignited thereby, it would normally be'disposed to emit fuel in theimmediate vicinity of the flame about 16 for ignition thereby whencontrol unit 39 operates a fuel valve in the supply line thereto. g i ir The safety control unit herein described is equally useful forinitiating any. other action produced by the heating of the controlelement 30 in response to any external intermittent actuation of a fuelsupply to fitting 3, and while the invention is described withparticular reference to a gas heating device, other uses arecontemplated. Many modifications of the structure illustrated arecontemplated within the scope of the invention.

What I claim is:

1. In a safety-control for a gaseous fuel pilot burner, means defining aconstant flame orifice .connected by a first conduit to a constant fuelsupply, a cupped flame spreadingelement having substantially verticalouter peripheral portions and arranged across and proximate to saidorifice as a flame holding device, an air injector jet member connectedto an intermittent fuel supply, a second conduit arranged coaxiallyadjacent said jet member to receive aerated fuel therefrom, said firstand second conduits being concentrically arranged one within the other,a lateral extension of the second conduit opening at one side of saidburner proximate to said constant flame orifice, flame-spreading hoodmeans adjustably attached to said first conduit for directing theflame'from said aerated fuel when ignited by the constant flame, andthermally responsive means disposed in the path of said directed flameas said intermittent supply is actuated.

2. In a burner control having a temperature responsive device forturning on a main burner in response to actuation of an auxiliary burnerupon demand signal actuation, a base, means in said base for receivingfuel controlled by said demand signal, a constant fluid fuel supply, anaerating jet member operatively connected at said base to fuel receivingmeans, a conduit mounted on said base aligned to receive aerated fuelfrom said jet member and terminating in a laterally extending auxiliaryburner, a second conduit mounted on said base and disposedconcentrically with first said conduit, being connected to said constantsupply and terminating in a burner orifice, hemispherically formed flameholding means disposed adjacent said orifice in flame spreading relationthereto, spring clip means engaging the outer one of said conduits andbearing said holding means in adjustable relation to said orifice, andflame spreading flanges arranged to distribute the flame from saidauxiliary burner along said temperature-sensitive element for theactuation thereof in response to auxiliary burner ignition.

3. In a safety pilot burner unit for intermittent actuation of thermalcontrol means mounted on a common base therefor, a burner nozzle forintermittently supplied fuel arranged facing said control means, meansat said base for connecting an intermittent fuel supply to said nozzleincluding a first conduit mounted proximately to the control means, asecond conduit mounted on said base to concentrically surround saidfirst conduit and terminate therebeyond in a low pressure orifice, saidsecond conduit being connected at said base to a constant fuel supplyfitting, said nozzle protruding laterally from said second conduitproximate to said orifice, flame spreading flanges variably attached tothe outer said conduit to variably spread flame from said nozzle alongsaid thermal control device, and 1a flame holding element ofsubstantially spherically convex form extending across said orifice toreceive a flame thereabout when fuel supplied thereto is ignited.

4. In a safety pilot burner unit for operating a thermal control elementin response to initiation of fuel flow thereat and including anintermittent fuel burner directed toward said control element and apilot orifice supplied from a constant fuel source, duct means carryingthe intermittently supplied fuel to said intermittent burner, secondduct means concentrically surrounding first said duct means terminatingat said orifice, paired flange means attached to second said duct meansarranged to direct fuel element, and convexly formed flame control meansdisposed across said orifice to radially distribute fuel flowingtherefrom for production of a stable circular flame therearound when thefuel is ignited.

5. In the burner unit of claim 4 said flame control means being ofcupped shape andhaving a circular pro trusion of less'diameter than saidorifice adjustably arranged for controlled partial closure thereof.

6. In' the burner of claim 4-said flange means and flame control meanshaving common means of support on said duct means for simultaneousvariable control of fuel effluent from said intermittent burner and saidorifice.

7. In avgaseous fuel ignition device responsive to intermittent controlof fuel in an auxiliary line and including a temperature responsivedevice forcontrolling an associated fuel supply, a nozzle arrangedfacing said device, a conduit connecting said auxiliary line to saidnozzle, a second conduit concentrically surrounding for part of itslength first said conduit and connected at one end to a a constant fuelsupply fitting, a burner orifice formed at the other end of said secondconduit proximate to said nozzle, first conduit being formed to causesaid nozzle to protrude laterally from a side wall of the secondconduit, and flame holding means of convex form adjacent said orificefor circularly spreading flame as the fuel from the orifice is ignited.v

8. In a fuel ignition device including a thermal safety control deviceand an intermittent auxiliary burner disduit toward said control device,and a flame holding member of cupped form having a convex face disposedacross said orifice to circularly spread fuel flowing from the orifice,said face having a protrusion thereon arranged to partially close saidorifice.

9. In a fuel ignition.device'including a thermal safety control deviceand an intermittent auxiliary burner disposed on a common base foractuation of the control device, a tubular conduit connected to aconstant fuel supply fitting mounted on said base, a burner orifice atone end of said conduit, a fuel duct concentrically mounted in saidconduit arranged to receive fuel from an intermittent auxiliary supplyand having a smooth flow lateral extension protruding from said conduittoward said control device to-form said auxiliary burner, flame controlmeans adjustably clamped by spring jaws on said conduit including flamespreader flanges positioned to spread flame from said auxiliary burneralong said control device, and a hemispherical flame holding memberdisposed with a convex face thereof in adjustably close abuttingrelation to said orifice for spreading fuel eflluent therefromcircularly about said member for stable retentionof flame when ignited,said face having a protrusion ;sheet metal, a pair of flanges laterallyextending from said base portion to form a narrow linear flame channelbeyond said burner nozzle facing the control element, an arm extendingfrom said base portion beyond said orifice, a cuppedflarne spreadersupported by said arm at flange jaws laterally extending from said baseportion for adjustable engagement with the sides of one conduit, saidjaws being resiliently disposed for adjustment longitudinally of theconduit engaged.

11. A flame control unit according to claim 10 wherein said cupped flamespreader is substantially a hemispherical member of diameter less thansaid engaged conduit whereby a small steady flame from the orificeenvelopes said spreader.

References Cited in the file of this patent UNITED ST ATES PATENTS160,789 Neil Mar. 16, 1875 Morick Apr. 12, Stocker Jan. 3, Brumbaugh etal Oct. 14, Mantz Nov. 31, Ray Sept. 11, Flagg Jan. 5, Biggle Apr. 27,Smoot May 3, Dolly Sept. 22,

FOREIGN PATENTS Germany July 28,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,159,203 December 1 1964 Aldo Zulian It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below In the grant (only),line 1, name of inventor, for "Aldo Julian" read Aldo Zulian Signed andsealed this 6th day of April 1965.,

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER AltestingOfficer

1. IN A SAFETY-CONTROL FOR A GASEOUS FUEL PILOT BURNER, MEANS DEFINING ACONSTANT FLAME ORIFICE CONNECTED BY A FIRST CONDUIT TO A CONSTANT FUELSUPPLY, A CUPPED FLAME SPREADING ELEMENT HAVING SUBSTANTIALLY VERTICALOUTER PERIPHERAL PORTIONS AND ARRANGED ACROSS AND PROXIMATE TO SAIDORIFICE AS A FLAME HOLDING DEVICE, AN AIR INJECTOR JET MEMBER CONNECTEDTO AN INTERMITTENT FUEL SUPPLY, A SECOND CONDUIT ARRANGED COAXIALLYADJACENT SAID JET MEMBER TO RECEIVE AERATED FUEL THEREFROM, SAID FIRSTAND SECOND CONDUITS BEING CONCENTRICALLY ARRANGED ONE WITHIN THE OTHER,A LATERAL EXTENSION OF THE SECOND CONDUIT OPENING AT ONE SIDE OF SAIDBURNER PROXIMATE TO SAID CONSTANT FLAME ORIFICE, FLAME-SPREADING HOODMEANS ADJUSTABLY ATTACHED TO SAID FIRST CONDUIT FOR DIRECTING THE FLAMEFROM SAID AERATED FUEL WHEN IGNITED BY THE CONSTANT FLAME, AND THERMALLYRESPONSIVE MEANS DISPOSED IN THE PATH OF SAID DIRECTED FLAME AS SAIDINTERMITTENT SUPPLY IS ACTUATED.